Cysteine-independent inhibition of the CFTR chloride channel by the cysteine-reactive reagent sodium (2-sulphonatoethyl) methanethiosulphonate

BACKGROUND AND PURPOSE

Methanethiosulphonate (MTS) reagents are used extensively to modify covalently cysteine side chains in ion channel structure-function studies. We have investigated the interaction between a widely used negatively charged MTS reagent, (2-sulphonatoethyl) methanethiosulphonate (MTSES), and the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel.

EXPERIMENTAL APPROACH

Patch clamp recordings were used to study a 'cys-less' variant of human CFTR, in which all 18 endogenous cysteine residues have been removed by mutagenesis, expressed in mammalian cell lines. Use of excised inside-out membrane patches allowed MTS reagents to be applied to the cytoplasmic face of active channels.

KEY RESULTS

Intracellular application of MTSES, but not the positively charged MTSET, inhibited the function of cys-less CFTR. Inhibition was voltage dependent, with a K(d) of 1.97 mmol x L(-1) at -80 mV increasing to 36 mmol x L(-1) at +80 mV. Inhibition was completely reversed on washout of MTSES, inconsistent with covalent modification of the channel protein. At the single channel level, MTSES caused a concentration-dependent reduction in unitary current amplitude. This inhibition was strengthened when extracellular Cl(-) concentration was decreased.

CONCLUSIONS AND IMPLICATIONS

Our results indicate that MTSES inhibits the function of CFTR in a manner that is independent of its ability to modify cysteine residues covalently. Instead, we suggest that MTSES functions as an open channel blocker that enters the CFTR channel pore from its cytoplasmic end to physically occlude Cl(-) permeation. Given the very widespread use of MTS reagents in functional studies, our findings offer a broadly applicable caveat to the interpretation of results obtained from such studies.

Surface magnetism in amine-capped ZnO nanoparticles

Magnetic behaviors of pure ZnO nanoparticles have been investigated both experimentally and theoretically. It is found that monodisperse ZnO nanoparticles wrapped with oleylamine with an average particle size of about 9.6 nm prepared by thermal decomposition do show ferromagnetic behavior with a saturation magnetization of about 34 memu g(-1) and coercive force of about 22 Oe, whereas ZnO nanoparticles with an average particle size of 5.2 nm prepared by ultrasonic irradiation without solvents show a weak ferromagnetic property with a saturation magnetization of about 0.12 memu g(-1) and coercive force of about 150 Oe at ambient temperature. First-principles calculations reveal that the 2p holes on the atoms at the surface (dangling bond of O atoms at ZnO(0001) or 2p electrons of N atom in NH(3) adsorbed on Zn(0001)) could be the source for the magnetic behavior of oxide nanoparticles.

The shine problem in hair: review of imaging methods and measures for luster

There is a need for both a better understanding of the technical drivers of shiny appearance in hair and for standard methods and measures of shine. To this end, we develop standard treatment methods for changing hair shine and examine a number of image-based measurements of luster. Using psychophysical techniques to get a perceptual reference, we find that available technical measures are difficult to use when trying to quantify the small changes in shine associated with treatment.

Dynamic gadolinium-enhanced MRI in early ischaemia of the proximal femoral epiphysis--a preliminary study

AIM

To compare the sensitivities of dynamic Gadoteridol (Gd)-enhanced magnetic resonance imaging (MRI) and conventional Gd-enhanced spin-echo (SE) T1-weighted imaging (WI) in the detection of decreased perfusion of early epiphyseal ischaemia, and to determine the contribution of metaphyseal vascularity to physeal perfusion in epiphyseal vascular occlusion by dynamic Gd-enhanced MRI.

MATERIALS AND METHODS

Twenty-eight 2-week-old piglets were divided evenly into four groups: control groups A and B, and ischaemic groups A and B (seven animals in each). In the ischaemic groups, MRI was performed bilaterally on hips in persistent hyperabduction for 30 min. In the control and ischaemic group A the piglets underwent dynamic Gd-enhanced MRI, and in control and ischaemic group B the piglets were subjected to Gd-enhanced SE T1WI.

RESULTS

In ischaemic group A, the enhancement ratio (ER) and enhancement speed (ES) of the various tissues (except the metaphysis) were significantly lower than those in control group A on dynamic Gd-enhanced MRI (p<0.05). However, in ischaemic group B, no significant decrease in the ER of each tissue was found, compared with the ER in control group B as viewed using Gd-enhanced SE T1WI (p>0.05). On dynamic Gd-enhanced MRI, the ER and ES of the physis were less than those of metaphysis in the ischaemic group A (p<0.05); however, the ER and ES of the physis were similar to those of metaphysis in control group A (p>0.05).

CONCLUSION

Dynamic Gd-enhanced MRI is more sensitive than conventional Gd-enhanced SE T1WI in the detection of early epiphyseal ischaemia. Physeal perfusion might be from the metaphysis in epiphyseal vascular occlusion.

Identification of a novel allele HLA-DRB1*0114 in two Chinese marrow donors by sequence-based typing

A novel human leukocyte antigen (HLA) class II, DRB1*0114, has been identified in routine typing of bone marrow donors for the Chinese Marrow Donor Registry in Shaanxi, China. The DRB1*0114 allele differs from DRB1*0101 by three nucleotide substitutions, causing two amino acid changes.

Renal artery aneurysm: diagnosis and surveillance with multidetector-row computed tomography

PURPOSE

To investigate the prevalence of renal artery aneurysms, and to assess the value of multidetector-row computed tomography (MDCT) in diagnosing renal artery aneurysms.

MATERIAL AND METHODS

Altogether, 862 patients underwent arterial-phase contrast-enhanced CT scan of the abdomen in the period November 2003 to October 2005. A search for renal artery aneurysms was performed in our reporting system and revealed six patients with renal artery aneurysm (RAA).

RESULTS

The incidence of RAA was 0.7%. All renal artery aneurysms were solitary, located in the main trunk or the first branch of the renal artery, with sizes from 1.5 cm to 3.4 cm. Five aneurysms were saccular, one fusiform. No underlying thrombosis was seen. Extensive calcification was found in one aneurysm. Three aneurysms were diagnosed using axial images, while three aneurysms were only displayed by volume rendering and maximum-intensity projection images.

CONCLUSION

This study demonstrates a 0.7% incidence of renal artery aneurysms in a total of 862 patients. MDCT has an important role in detecting and assessing renal artery aneurysms. Some aneurysms can only be displayed by post-processing techniques such as volume rendering and maximum-intensity projection.

Beta-lapachone inhibits proliferation and induces apoptosis in retinoblastoma cell lines

AIMS

To investigate the cytotoxicity of beta-lapachone, a potent agent that may selectively target tumour cells, in retinoblastoma (RB) cell lines.

METHODS

Growth inhibitory effects of beta-lapachone were evaluated in Y79, WERI-RB1, and RBM human retinoblastoma cell lines. Pro-apoptotic effects of beta-lapachone were evaluated in Y79 cells by detection of caspase 3/7 activity, by enzyme-linked immunosorbent assay for nucleosome fragments, and by cellular morphological analysis.

RESULTS

Beta-lapachone induced significant dose-dependent growth inhibitory effects in all three retinoblastoma cell lines. The 50% growth inhibitory concentration (IC(50)) of this agent was 1.9 microM in Y79 cells, 1.3 microM in WERI-RB1 cells, and 0.9 microM in RBM cells. Beta-lapachone also induced proapoptotic effects in RB cells. Treatment of Y79 cells with 1.9 microM beta-lapachone (IC(50)) resulted in a peak, fourfold induction of caspase 3/7 activity at 72 h post-treatment; a peak, 5.6-fold increase in nucleosome fragments at 96 h post-treatment; and a peak, 1.7-fold increase in the frequency of apoptotic cells at 48 h post-treatment, relative to vehicle-treated controls.

CONCLUSION

Beta-lapachone induced potent cytotoxic effects in RB cell lines at low micromolar concentrations, suggesting this agent could be useful in the clinical management of RB.

Imaging of primary adrenal lymphoma: case report and literature review

Primary adrenal lymphoma is very rare, and correct preoperative diagnosis is difficult because of its nonspecific imaging findings. We report a case of bilateral primary adrenal lymphoma, with the largest dimension of 18 cm, which is the largest one reported so far, to our knowledge. Computed tomography (CT) and magnetic resonance (MR) findings were not specific enough to establish a correct diagnosis, but positron emission tomography/CT (PET/CT) showed high fluorodeoxyglucose (FDG) uptake, indicating its malignant nature. We describe the imaging findings and review the related literature to highlight this uncommon entity.

Archaea predominate among ammonia-oxidizing prokaryotes in soils

Ammonia oxidation is the first step in nitrification, a key process in the global nitrogen cycle that results in the formation of nitrate through microbial activity. The increase in nitrate availability in soils is important for plant nutrition, but it also has considerable impact on groundwater pollution owing to leaching. Here we show that archaeal ammonia oxidizers are more abundant in soils than their well-known bacterial counterparts. We investigated the abundance of the gene encoding a subunit of the key enzyme ammonia monooxygenase (amoA) in 12 pristine and agricultural soils of three climatic zones. amoA gene copies of Crenarchaeota (Archaea) were up to 3,000-fold more abundant than bacterial amoA genes. High amounts of crenarchaeota-specific lipids, including crenarchaeol, correlated with the abundance of archaeal amoA gene copies. Furthermore, reverse transcription quantitative PCR studies and complementary DNA analysis using novel cloning-independent pyrosequencing technology demonstrated the activity of the archaea in situ and supported the numerical dominance of archaeal over bacterial ammonia oxidizers. Our results indicate that crenarchaeota may be the most abundant ammonia-oxidizing organisms in soil ecosystems on Earth.

Ribosomal RNA as molecular barcodes: a simple correlation analysis without sequence alignment

MOTIVATION

We explored the feasibility of using unaligned rRNA gene sequences as DNA barcodes, based on correlation analysis of composition vectors (CVs) derived from nucleotide strings. We tested this method with seven rRNA (including 12, 16, 18, 26 and 28S) datasets from a wide variety of organisms (from archaea to tetrapods) at taxonomic levels ranging from class to species.

RESULT

Our results indicate that grouping of taxa based on CV analysis is always in good agreement with the phylogenetic trees generated by traditional approaches, although in some cases the relationships among the higher systemic groups may differ. The effectiveness of our analysis might be related to the length and divergence among sequences in a dataset. Nevertheless, the correct grouping of sequences and accurate assignment of unknown taxa make our analysis a reliable and convenient approach in analyzing unaligned sequence datasets of various rRNAs for barcoding purposes.

AVAILABILITY

The newly designed software (CVTree 1.0) is publicly available at the Composition Vector Tree (CVTree) web server http://cvtree.cbi.pku.edu.cn.

Measurement of the electronic transition dipole moment by Autler-Townes splitting: Comparison of three- and four-level excitation schemes for the Na2AΣu+1−XΣg+1 system

We present a fundamentally new approach for measuring the transition dipole moment of molecular transitions, which combines the benefits of quantum interference effects, such as the Autler-Townes splitting, with the familiar R-centroid approximation. This method is superior to other experimental methods for determining the absolute value of the R-dependent electronic transition dipole moment function mu(e)(R), since it requires only an accurate measurement of the coupling laser electric field amplitude and the determination of the Rabi frequency from an Autler-Townes split fluorescence spectral line. We illustrate this method by measuring the transition dipole moment matrix element for the Na2 A 1Sigma(u)+ (v' = 25, J' = 20e)-X 1Sigma(g)+ (v" = 38, J" = 21e) rovibronic transition and compare our experimental results with our ab initio calculations. We have compared the three-level (cascade) and four-level (extended Lambda) excitation schemes and found that the latter is preferable in this case for two reasons. First, this excitation scheme takes advantage of the fact that the coupling field lower level is outside the thermal population range. As a result vibrational levels with larger wave function amplitudes at the outer turning point of vibration lead to larger transition dipole moment matrix elements and Rabi frequencies than those accessible from the equilibrium internuclear distance of the thermal population distribution. Second, the coupling laser can be "tuned" to different rovibronic transitions in order to determine the internuclear distance dependence of the electronic transition dipole moment function in the region of the R-centroid of each coupling laser transition. Thus the internuclear distance dependence of the transition moment function mu(e)(R) can be determined at several very different values of the R centroid. The measured transition dipole moment matrix element for the Na2 A 1Sigma(u)+ (v' = 25, J' = 20e)-X 1Sigma(g)+ (v" = 38, J" = 21e) transition is 5.5+/-0.2 D compared to our ab initio value of 5.9 D. By using the R-centroid approximation for this transition the corresponding experimental electronic transition dipole moment is 9.72 D at Rc = 4.81 A, in good agreement with our ab initio value of 10.55 D.

Photoassociative production and trapping of ultracold KRb molecules

We have produced ultracold heteronuclear KRb molecules by the process of photoassociation in a two-species magneto-optical trap. Following decay of the photoassociated KRb*, the molecules are detected using two-photon ionization and time-of-flight mass spectroscopy of KRb+. A portion of the metastable triplet molecules thus formed are magnetically trapped. Photoassociative spectra down to 91 cm(-1) below the K(4s)+Rb(5p(1/2)) asymptote have been obtained. We have made assignments to all eight of the attractive Hund's case (c) KRb* potential curves in this spectral region.

Functional expression of ATM gene carried by HSV amplicon vector in vitro and in vivo

Ataxia-telangiectasia (AT) is a human autosomal recessive disease with a pleiotropic phenotype characterized by cerebellar degeneration, immunodeficiency, premature aging, cancer predisposition, and radiation sensitivity. The gene mutated in AT, ATM (for AT-mutated), had been cloned and found to have ionizing radiation and oxidative stress-inducible kinase activity. No treatment can stop the progression of the disease. In this study, the complete open-reading frame of ATM cDNA was cloned into a Herpes simplex virus type-1 (HSV-1) amplicon vector (pTO-ATM), and the transduction of cultured AT cells was demonstrated by immunohistochemistry and Western blot analysis. Functional gene expression was evaluated by cell colony-forming assays following exposure to oxidative stress. The survival of AT cells with ATM gene transduction was about 100% higher compared to nontransduced cells after t-butyl hydroperoxide treatments. Next, the normal ATM gene expression in different regions of the rat brain was studied. Immunohistochemistry staining demonstrated weak endogenous ATM protein expression in neurons of the caudate-putamen, with significantly higher levels of expression detected in neurons in other brain regions. Exogenous ATM gene expression from pTO-ATM after viral transduction in the caudate-putamen of the adult rat was examined. At 3 days after injection of the pTO-ATM viral vector, abundant positive ATM staining of the neurons was found at the injection sites, in comparison to the controls. These data demonstrate that the relatively large ATM cDNA can be transduced and expressed in vitro and in vivo from an HSV amplicon viral vector. These data provide initial evidence that the replacement of the ATM gene into the cells of AT patients might be possible some day.

[Long-term follow-up result of near-total laryngectomy in senile patients with laryngeal carcinoma]

OBJECTIVE

To study the long-term follow-up result of near-total laryngectomy in senile patients with laryngeal carcinoma.

METHOD

Twelve patients who were above 65 years old and underwent near-total laryngectomy from 1990 to 1996 were summarized. Twelve patients with quamous cell carcinoma of larynx were conformed. We adopted and improved Parson's operation, remained normal side cricoid cartilage plate, cricoarytenoid joint and recurrent laryngeal nerve.

RESULT

Three year and five year survival rates were 75.0% and 66.7% respectively. All patients had good swallowing founction in two weeks after operation. Ten patients obtained good speech function.

CONCLUSION

The authors believed that near total laryngectomy was safe and beneficial to senile patients with laryngeal cancers who suffered from foundermental disease in heart, lung or brain.

Immobilized MICA could expand human Vdelta1 gammadelta T cells in vitro that displayed major histocompatibility complex class I chain-related A-dependent cytotoxicity to human epithelial carcinomas

Human major histocompatibility complex class I chain-related A (MICA) is a human leucocyte antigen-related polymorphic molecule, which is expressed on many kinds of epithelial tumours and can be recognized by the Vdelta1 subset of gammadelta T cells. In the present study, monoclonal antibodies (MoAbs) were produced in mice immunized with recombinant MICA (rMICA)*008. It was found that MICA was expressed on ovarian and colonic tumour tissues and could be detected by these anti-MICA MoAbs. The immobilized rMICA could induce the proliferation of human ovarian epithelial carcinoma- or colonic carcinoma-derived gammadelta T cells of the Vdelta1 phenotype in vitro. These Vdelta1 T cells displayed a strong, broad-range cytolytic activity towards tumour cell lines positive for MICA. The efficiency of this cytolytic activity depended greatly on the level of MICA expressed on the cell surface and could be inhibited by anti-MICA MoAbs. Therefore, MICA may play an important role in immune responses against epithelial tumours and function as a stimulating factor for the growth of Vdelta1 gammadelta T cells, whereas MICA-reactive Vdelta1 gammadelta T cells might serve as a new candidate for adoptive cellular therapy of tumours.

Total-internal-reflection mode in holographic polymer dispersed liquid crystals

We have developed a holographic polymer dispersed liquid-crystal device based on total internal reflection (TIR). In the field-off state, the holographic planes are slanted such that the angle of the diffraction beam is beyond the TIR angle of the glass substrate. The beam is trapped in the sample and propagates to the edge. In the field-on state, the holographic grating is erased and the incident beam propagates directly through the sample. Contrast ratios of 10 dB, submillisecond response times, and an index modulation of 0.042 at 1550 nm are reported.

Tunable face-centered-cubic photonic crystal formed in holographic polymer dispersed liquid crystals

We report on the fabrication and electro-optic measurements of face-centered-cubic (fcc) lattices in holographic polymer dispersed liquid-crystal materials. Four linearly polarized coherent plane waves were interfered to generate a fcc optical lattice that was subsequently and indefinitely recorded as an arrayed pattern of nanometer-sized liquid-crystal droplets (approximately 50 nm) at lattice nodes within a polymer matrix. Observed transmission spectra and Kossel diffraction curves are consistent with fcc crystal structure. A completely reversible 2% wavelength shift of the (+/- 111) stop band was observed on application of an electric field.

Chemical profile of two types of oral snuff tobacco

The chemical-analytical profile of two US brands of oral moist snuff was determined. These two brands were bought in five geographical locations (NY, MA, CO, CA and KY in the US). They were mixed thoroughly to yield representative samples. Brand A had a pH of 5.84 and nicotine content of 0.42%, while brand B had a pH of 7.99 and nicotine content of 2.73%. At pH 5.84, only 1% of the nicotine is present as a free base while 59% of nicotine is present in unprotonated form at pH 7.99. It is the unprotonated form of nicotine that is most readily absorbed through the mucous membrane in the oral cavity. Snuff A contained also significantly lower levels of moisture, nitrate, nitrite and tobacco-specific nitrosamines than snuff B. The University of Kentucky reference snuff 1S3 was analyzed as an external control sample. These two snuff brands are currently being assayed with rats in a short-term and in long-term bioassays to test the concept that the tobacco-specific N-nitrosamines are major contributors to the carcinogenic activity of oral snuff.

[Unilateral tonsillar enlargement and malignant tonsillar lymphoma]

OBJECTIVE

To study clinic characters of malignant lymphoma in patients with unilateral tonsillar enlargement for early discover and synthetic therapy clinic characters of malignant lymphoma patients with unilateral tonsillar enlargement for early discover and synthetic therapy.

METHOD

10 cases of non-Hodgkin's lymphoma (NHL) out of 100 unilateral tonsillar enlargement patients given tonsillectomy were treated with combined chemotherapy. 8 cases of 10 underwent local radiotherapy after operation.

RESULT

5 years survival rate was 60% in 10 patients with NHL.

CONCLUSION

Progressing unilateral swollen tonsil found in a short time with suspicious appearance should be given tonsillectomy for histopathology; upper airway and systematic symptoms such as fever and rigors, night sweats; lymphatic enlargement in cervical, axillary, inguinal region; hepatosplenomegaly should be thought of main traits of malignant lymphoma, and hyposensitivity to medicine should be taken malignant lymphoma into account.